This device determines whether you will get a promotion and whether or not it will be possible to finish.
There is no set policy that has ever been officially explained.
what we know is the following are true.
1. Not everyone in the same market gets the same promotion
2. It's not based on rating,
3. It's not how long you have been driving (except for new driver bonuses/guarantees of course)
4. They will fight you tooth and nail over paying them
5. Some markets have none at all
6. Some of them will be 100% impossible to achieve (IE you need perfect acceptance rating 1.5 trips per hour and you cant get more than 1 per)
7. they are disappearing as we speak.